"Trailer hitching" problem

No end of things. Start with the cheap ones, get a dial guage & check the actual cam timing, then a lamda MAP, you might have the wrong progression drilings on the carb.

Nedavno Duncan Wood napisa:

As I wrote problem exists both with (correctly tuned) original distributor ignition system, and the one I fitted (Ford EDIS based) programmable distributorles ignition system.

I tried advancing / retarding ignition around 2000 rpm, and it did not help.

As a part of the new ignition system I have MAP sensor and I can log MAP as I drive. What do I look for? Whit is lamda? Do you mean lambda sensor? I do not have it.

And I also changed carburetor, and even tested without it (LPG only). So perhaps I can rule out progression drilings (and I have the original, factory fitted carburetor too).

Check the cam is timed up right (not the ignition).

Nedavno Duncan Wood napisa:

And how do I do that? And wouldn't that create problems at any rpm, not just ~2000?

Set a dial guage on top of the engine & measure when the valves open. Then check it with the spec. It will reduce power at other rpm but not necessarily by very much. Does a little extra advance on the ignition have any effect on the stutter?

Nedavno Duncan Wood napisa:

Only now I realized that you wrote "check the actual cam timing". I missed word CAM, and that's why I was confused :-)

I do not think that this can be a problem. I have this car from new, and it has chain not timing belt. It was never touched, and car only has 35000 miles on the clock.

I tried to advance / retard timing at ~2000 rpm - nothing.